Made by Bell & Gossett
The pressure relief valve is another safety device which releases boiler and system pressure should it exceed a preset level. The normal pressure settings of these devices for a residential or light commercial low pressure boiler systems is 30-45psi. The preset level should never exceed the maximum operating pressure of the boiler as set by the manufacturer. The only recommended relief valve style should contain a manual lift-lever which will allow the system maintenance technician to manually test the discharge abilites of the valve periodically.